Occupational exposure to particulate matter from three agricultural crops in California.

Agricultural work is a major contributor to California's and the nation's economy and employs a large number of workers. However, agricultural work can have numerous risks, such as exposure to elevated levels of particulate matter (PM) and other airborne pollutants with potential adverse health effects. To determine the magnitude of occupational exposures, PM levels were assessed for 89 workers from three major crops in California; almonds, melons and tomatoes. Personal samples were collected for PM2.5 and inhalable PM using personal sampling equipment. Geometric mean concentrations from personal exposure for workers in almonds (inhalable PM=4368 μg/m(3), PM2.5=122 μg/m(3), N=5), tomatoes (inhalable PM=1410 μg/m(3), PM2.5=12 μg/m(3), N=33), and melons (inhalable PM=1118 μg/m(3), PM2.5=19 μg/m(3), N=51) showed high PM exposure when working with these three crops. Large exposure differences by crop were more common than by task (i.e. harvesting, packing and weeding) among the three crops studied. This is the largest study of agricultural workers engaged in hand harvesting, a significant employer of farm labor, and relatively high levels of exposure to PM were measured.